A stork’s-bill seed falls to the ground. It carries a twisted spiral awn, and that spiral coils and then uncoils with the humidity of the air. With each cycle, the seed drives itself a little deeper. It screws itself into the earth without the plant having spent a single calorie, all the energy comes from the climate. Erodium cicutarium is a weed of waste ground, we walk over it without seeing it. Stefano Mancuso reads in it the blueprint for an autonomous probe capable of drilling into soil, including on another planet, and he draws from it the question that holds the whole of The Revolutionary Genius of Plants together: “Imagine how many possible applications you could find for a material capable of moving using nothing but humidity gradients.”
That is the whole shift of this book compared with the previous one. Brilliant Green set out to demonstrate that the plant feels, remembers and decides. This one takes the matter as settled and moves into the workshop. The Italian title says it plainly, Le piante hanno già inventato il nostro futuro, plants have already invented our future. The French edition preferred La Révolution des plantes, vaguer, less sharp.
Nine chapters, nine machines
The book has nine chapters, a preface, and a great many photographs. A delicious detail for anyone who enjoys what goes on behind the scenes in publishing: the American edition simply changed the order of the chapters, which says a great deal about how independent they are. Each one stands on its own, and follows roughly the same trajectory: a human problem, a plant solution already there, a technical prototype.
The first chapter, “Memories without a Brain”, is a historical investigation in three stages, and it is the finest piece in the volume. Lamarck observes that Mimosa pudica, when harassed, eventually stops folding its leaves, and he calls this fatigue. Desfontaines takes up the matter and shows that the plant adapts to a repeated disturbance instead of exhausting itself. Tradition tells of mimosas driven around Paris in a carriage, which stop closing up after the first jolts, but I did not find this detail in Mancuso’s own pages, I report it for what it is worth. Two centuries later, Monica Gagliano designs an experiment to verify what Desfontaines had seen. Mancuso then writes: “We managed to prove that plants can learn that a given stimulus was harmless and distinguish it from others that are potentially dangerous, and that they are able to remember a past experience.” The “we” is not an author’s affectation, he co-signed the paper.
The chapter on movement also opens on the story of a tool. In 1896, the botanist Wilhelm Pfeffer shoots the first time-lapse film devoted to plants. His model is not a scientist, it is Muybridge and his racehorse broken down frame by frame. Around him, Julius von Sachs sneers. Mancuso sums up the gain in one well-chosen phrase: “With the invention of time-lapse photography, Pfeffer gave botanists a tool to make visible what had been invisible.” There follows a distinction that the book then uses everywhere, between active movements, which consume energy through control of cell pressure (the opening of the stomata, flowering, the trap of the Venus flytrap), and passive movements, which draw on the environment, such as the opening of conifer cones.
The Chilean puzzle
The most unsettling case in the book is called Boquila trifoliolata. It is a very common vine of the temperate Chilean forests, and it changes the shape, the size and the colour of its leaves according to the species it climbs on. Careful not to misread this, it is not one species imitating another once and for all. A single individual carries several types of foliage at the same time, each shoot conforming to whatever it touches. The supposed advantage is deterring herbivores, imitating a toxic plant is protection.
The question remains, and Mancuso does not close it. Through what channel does the vine know what its neighbour looks like? He mentions the perception of odours, he mentions a rudimentary visual capacity, he leaves it open. I count that in his favour, because this is precisely the case that would have served a strong thesis best, and he refuses to cash it in.
The same chapter tells the story of rye, which is worth a novel of its own. Coming from Turkey, this cereal was at first a weed in wheat fields. By imitating wheat, it escaped hand weeding, until farmers ended up growing it for its own sake. This is what is called Vavilovian mimicry, after Nikolai Vavilov, and Mancuso draws from it a reversal that stopped me dead: “each time people decided which characteristics to select for cultivation, the so-called weeds learned to respond to those preferences”. Our selection has become an evolutionary pressure to which the plant replies. The contemporary sequel is called glyphosate, and Palmer amaranth, Amaranthus palmeri, resists it so well that the doses go up, which selects for still more resistance.
Then comes the funniest chapter, the one on capsicophages, the chilli eaters. Mancuso recounts his own excesses there, Scoville scale in hand. Capsaicin releases endorphins, hence pleasure, through a mechanism comparable to that of other addictions, and what the enthusiast is after, he writes, “is capsaicin and nothing else, in increasing doses”. The classic theory stumbles on this, it calls it the drug-reward paradox, since evolution should not have produced a molecule that drives people to consume more of the plant. Mancuso turns the glove inside out. The chilli has made humanity dependent, and “the strategy this species implemented to make humans dependent on it has proved to be a success.” Same logic with the acacias, which house and feed ants fierce enough to attack animals “whose size is billions of times greater than their own”, ants that recent work shows to be chemically manipulated for the benefit of the tree.
Copying, literally
The “Archiplants” chapter lines up the transfers. Leonardo da Vinci studies phyllotaxis and understands the arrangement “that guarantees the leaves the best exposure to light, without them shading one another”, from which the architect Saleh Masoumi today derives a residential tower. In the nineteenth century Joseph Paxton grows the giant water lily Victoria amazonica, observes the veining of its leaf, and from that builds the Crystal Palace of the London Exhibition of 1851. The columns of the temple of Luxor imitate the papyrus stem, the Corinthian capital carries acanthus leaves. Cacti, for their part, inspire buildings that capture humidity from the air, such as the Warka Tower credited with nearly a hundred litres of water a day in Ethiopia, an order of magnitude that I have from the book alone, without having cross-checked it elsewhere.
Two projects are his own, and he recounts them from the inside, failures included. The Jellyfish Barge is a floating greenhouse designed with the architects Cristiana Favretto and Antonio Girardi, which desalinates seawater using the sun by imitating the natural water cycle. The prototype works, it grows vegetables, it is presented at the Milan Expo in 2015 and showered with awards. No investor follows. Mancuso writes it without shielding himself: “Even though it pulls off the apparent miracle of producing vegetables without consuming any resources, the market does not seem to care much.” And this sentence, the most bitter in the book, “either the projects win prizes, or they go to market”.
The other undertaking, carried out with Barbara Mazzolai, is plantoids, robots designed no longer on the animal model but on that of the root. The argument comes down to a list of specifications: “Plants consume very little energy, they perform passive movements, they are built in modules, they are robust, they have a distributed intelligence.” The underlying principle is an entirely different mode of locomotion, growth instead of movement. A single cereal plant, he notes, develops a linear length of roots and root hairs on the order of nineteen kilometres.
The chapter nobody expected
Then the book tips over into politics, and barely announces it. “Green Democracies” starts from the swarm of bees and arrives at Wikipedia and cooperatives, by way of popular juries and Athenian democracy. The pivotal formula is this one: “In nature, large distributed organisations without control centres are always the most efficient.” Mancuso goes so far as to write that our individual decisions are collective too, our neurons working like bees choosing the site of a hive. From this he draws a demographic optimism that runs against the current, the three and a half billion additional humans expected by 2050 being for him “an enormous resource” and not a burden.
This is where the book shows its manufacturing flaw. We move from biology to architecture, from architecture to political theory, from politics to robotics, without transition and sometimes without demonstration. The unity comes from the thesis, copy the plants, not from the reasoning. Some pages amount to a plea for his own research programmes. He writes alone this time, Alessandra Viola is no longer there, and you can hear it: more personal, more anecdotal, less tight. Each chapter opens with a literary epigraph, Huxley, Murakami, Darwin, David Foster Wallace, Carl Sagan to finish, with this sentence that I keep: “A blade of grass is a commonplace on Earth; it would be a miracle on Mars.”
What I take away from it fits in one line. An organisation without a centre is not a failure of organisation, it is another way of solving problems, and immobility is what forces it. I have been circling this idea for months without having been able to put it that way.
A word on the quotations given here: I translated them from the American edition, so they do not follow the French text word for word.
Read in April 2019. Note written in 2026.
